Forging machine transfer

ABSTRACT

A transfer system is disclosed for progressively transferring work pieces between die stations of a progressive forging machine. The transfer includes a pivoted frame on which a reciprocating slide is supported. Work pieces gripping fingers are carried by the slide for movement from a gripping position to a release position. Pivotal movement of the frame moves the fingers out away from the die face to provide clearance for turning of the fingers. Finger turning is in response to reciprocation of the finger supporting slide. A first cam driven linkage controls the oscillating pivotal movement of the frame and a second cam driven linkage controls the gripping and release of the fingers. The two linkages are arranged to be substantially unaffected by the pivotal movement of the frame and the reciprocating movement of the slide. The transfer is arranged to permit easy removal of one slide with work piece gripping fingers thereon and the substitution of a different slide with a different type of work piece gripping fingers. Therefore, the transfer system can be easily modified to accommodate different types of work pieces and to permit different types of forming operations within a single machine.

United States Patent it McClellan et al.

[451 Aug. 22, 1972 i541 FORGING MACHINE TRANSFER Tifiin, Ohio [73] Assignee: The National Machinery Company,

Tiffm, Ohio [22] Filed: June 26, 1970 [21] Appl. No.: 50,223

[52] US. Cl ..10/12 T, 72/421, 72/405 [51] Int. Cl. ..B2ld 43/02 [58] Field ofSearch ..10/12T, 12.5, 11 T, 12 R, 10/11 R, 76 T; 72/405, 421, 358

[56] References Cited UNITED STATES PATENTS 3,165,766 1/1965 Wisebaker ..10/12 T 3,259,929 7/1966 Van De Meerendonk 10/76 T 2,272,592 2/1942 Wilcox ..10/12 T 2,278,103 3/1942 Friedman ..10/12 T 2,648,077 8/1953 Friedman ..10/12 T 2,728,267 12/1955 Schaelfer ..10/12 T 2,825,075 3/1958 De Loe ..10/12 T 3,604,242 9/1971 Allebach ..72/421 FOREIGN PATENTS OR APPLICATIONS 863,838 3/1961 Great Britain ..10/l2 T Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby AtrorneyMcNenny, Farrington, Peame & Gordon ABSTRACT A transfer system is disclosed for progressively transferring work pieces between die stations of a progres sive forging machine. The transfer includes a pivoted frame on which a reciprocating slide is supported. Work pieces gripping fingers are carried by the slide for movement from a gripping position to a release position. Pivotal movement of the frame moves the fingers out away from the die face to provide clearance for turning of the fingers. Finger turning is in response to reciprocation of the finger supporting slide. A first cam driven linkage controls the oscillating pivotal movement of the frame and a second cam driven linkage controls the gripping and release of the fingers. The two linkages are arranged to be substantially unaffected by the pivotal movement of the frame and the reciprocating movement of the slide. The transfer is arranged to permit easy removal of one slide with work piece gripping fingers thereon and the substitution of a different slide with a different type of work piece gripping fingers. Therefore, the transfer system can be easily modified to accommodate different types of work pieces and to permit different types of forming operations within a single machine.

19 Claim, 10 Drawing Figures PATENTED M1822 1912 SHEET 2 0F 7 PATENTEI] we 22 I972 SHEET 5 [IF 7 l N V E NTORS FORGING MACHINE TRANSFER BACKGROUND OF THE INVENTION This invention relates generally to machines for progressively cold forming work pieces and more particularly to a novel and improved automatic transfer for such machines.

PRIOR ART Various types of forging machines are provided to progressively form parts at a plurality of die stations. In many instances rod or wire stock is fed into the machine and is cut into blanks or slugs which are then progressively transferred to a plurality of die stations in which they are progressively formed to the desired shape. In the past it has been customary to construct a given machine for use in the manufacture of a particular type of product and to provide a transfer which is suitable only for transferring such product.

For example, when a machine is intended for forming relatively long header parts, such as bolts or the like, the practice has been to equip the machine with a transfer which is incapable of turning the blank between the die stations and which is provided with gripper fingers that open wide enough to clear the relatively large tools often required for such heading operations. An example of such a machine is illustrated in the US. Pat. No. 2,278,103.

In other instances, the machine is used to form relatively short parts which must be turned end-for-end between at least some of the die stations. Such a machine is often equipped with a transfer operable to transfer parts between die stations selectively with or without turning. An example of such a transfer is illustrated in the US. Pat. No. 3,165,766.

Another transfer for this general category of parts is a transfer of the type used in the manufacture of nuts. Such transfers are often arranged so that the fingers are spring biased toward the closed or gripping position and are not mechanically opened for release of the part. Instead, the part or fingers are arranged to cause the fingers to cam apart slightly as the part is pressed into the fingers when it is ejected from the die. The subsequent tool then pushes the part out of the fingers into the subsequent die. In the past, the type of parts which could be manufactured in a particular machine was limited to the type of part which could be conveniently transferred by the transfer installed on the machine. Therefore, if such a machine was provided with a transfer which was capable of transferring headed parts and incapable of turning a blank end-for-end, parts requiring such turning movement could not be manufactured on such machine. On the other hand, if the machine was equipped with a transfer capable of tuming the parts and incapable of handling headed parts or relatively long parts, the machine could not be used for manufacturing of elongated or headed parts.

SUMMARY OF THE INVENTION The present invention is directed to a novel and improved transfer for automatically and sequentially transferring parts between a plurality of die stations. The transfer assembly is arranged so that it can be easily modified to permit a change over from a mechanism particularly suited for the transfer of relatively long or headed parts without turning the parts end-for-end to a transfer particularly suited for turning blanks end-forend. Consequently, a machine incorporating a transfer in accordance with the present invention is more versatile in that the transfer can be modified easily and conveniently so that the machine can be used to manufacture several difi'erent categories of parts.

There are a number of different aspects to the present invention. In accordance with one aspect of this invention a transfer is provided in which the part or blank gripping fingers are supported on a reciprocating slide for simple reciprocating movement. Such slide is easily removed from the transfer to permit substitution of another slide having a different type of blank gripping fingers thereon. Since the slide with the gripping fingers supported thereon is easily removed from the machine, the setup of the fingers and adjustment for a particular part can be easily accomplished in a separate fixture or jig. Therefore, the down time of the machine required for change over is minimized.

In accordance with another aspect of this invention the transfer is provided with a forward slide supporting frame pivoted for oscillating movement with respect to the die breast of the frame in combination with cam driven power means arranged to cause such oscillating movement. The slide is carried on the oscillating frame for simple reciprocating movement with respect thereto. The oscillation of the frame causes blank gripping fingers carried by the slide to swing away from the die breast to provide clearance when blank turning is required. This same movement causes a lifting of the fingers and can be used to raise the fingers up enough to clear the punch to permit finger return movement to commence before the punch is withdrawn clear of the fingers. Also, such swinging movement is used in some instances to move blanks out of the dies at one station and into the dies at a subsequent station. The drive for causing oscillation of the forward frame section can be disconnected easily when the transfer mechanism does not require such oscillating movement. For example, such oscillating pivotal movement is not normally required when the transfer does not involve turning of the blank as it is transferred between adjacent stations.

In accordance with another aspect of this invention a novel and improved turn around gripper structure is provided. In the illustrated embodiment the gripper assembly is pivoted for oscillating movement about a vertical center axis. A pneumatic spring mounted along the pivot axis provides the finger gripping force. The various elements of the gripper assembly are arranged to facilitate easy adjustment.

In accordance with still another aspect of this invention, a novel and improved transfer drive is provided which incorporates an overload clutch mechanism which is substantially immuned to malfunction.

These and other aspects of the invention are described in the following detailed description of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of the preferred transfer incorporating the present invention with parts removed for purposes of illustration;

FIG. 2 is an end view of the transfer illustrated in Figure l;

FIG. 3 is a cross section taken generally along 33 of Figure l with parts removed for purposes of illustration;

FIG. 4 is a fragmentary schematic perspective illustrating the drive mechanism for pivotally oscillating the forward transfer frame;

FIG. 5 is a fragmentary schematic perspective illustrating the linkage for controlling the opening and closing movement of the transfer fingers;

FIG. 6 is a fragmentary front elevation of a novel and improved gripper transfer assembly which is operable to transfer a work piece or the like selectively with or without turning during transfer;

FIG. 7 is a longitudinal section taken along 77 of FIG. 6 illustrating the structural detail of the transfer illustrated in FIG. 6;

FIG. 8 is a fragmentary schematic perspective view similar to FIG. 5 illustrating the gripper operating linkage in combination with non-tuming transfer grippers;

FIG. 9a is a side elevation partially in section of the drive for reciprocating the transfer slide, and;

FIG. 9b is a fragmentary plan view of the drive illustrated in Figure 9a.

DETAILED DESCRIPTION OF THE DRAWINGS The illustrated embodiment of this invention is a transfer for progressively transferring work pieces from one die station to the next in a progressive cold forging machine of the general type illustrated in application Ser. No. 784,806, filed Dec. 18, 1968, now US. Pat. No. 3,604,242. Such machines include a main frame in which a slide is reciprocable toward and away from a die breast supported in the frame. Usually, dies are mounted in the die breast at laterally spaced locations or die stations. Cooperating tools are provided on the slide at each die station and are arranged so that a work piece or blank is progressively formed in each die station until the desired product is obtained after the working of the last die station of the machine. In some instances machines of this nature are provided with means to supply separate work pieces to the machine for transfer to the first die station. A more common arrangement, however, provides for a feed of wire or rod stock into the machine to a shearing station wherein the stock is cut into blanks or work pieces. Such blanks or work pieces are then transferred to the first die station and subsequently to the remaining die stations. Such machines may be used to manufacture various types of parts. In some instances the blank is upset or headed as for example to form a bolt blank. In other in' stances, the blank is shaped so that it may be threaded and made into a nut. In still other instances, the machine is used to form other types of articles.

The present invention is directed to a novel and improved automatic transfer for a progressive cold forging machine or the like which may be used in the manufacture of a variety of different parts. The transfer can be used for relatively short parts and can be arranged to transfer the part between adjacent die stations either with or without turning as required for the manufacturing process. Similarly, the transfer may be used for longer parts including parts which involve heading such as bolt blanks or the like.

Referring to FIGS. 1 through 3, the illustrated transfer is mounted on the main forging machine frame 10 in a position above and substantially adjacent to the laterally extending die breast 11 illustrated in FIG. 3. Dies lla are mounted in the breast and cooperating tools 11b carried by the main slide cooperate with the dies to progressively form the work pieces. The transfer includes a support frame 12 which is pivotally supported at its rearward end by spaced pivot pins 13 (illustrated in FIGS. 1 and 2). The support frame 12 is provided with integrally formed generally curved support sections 14 which extend from opposite ends thereof to the pivot pins 13. The pivot pins 13 are mounted in a support assembly which is secured to the machine frame 10. The support assembly 16 is provided with means to provide both horizontal and vertical adjustment for accurate positioning of the support frame 12.

The support frame 12 is normally maintained in the position illustrated by a tow clamp assembly 17 located adjacent to each end of the support frame 12 adjacent to its forward edge. The tow clamp assembly 17 may be released when servicing is required to allow the entire transfer frame assembly to be pivoted up around the axis of the pivot pins 13.

A pivot frame 18 is supported at its ends by pivot pins 19 carried by the support frame 12 for oscillating movement about a pivot axis 21. Cam driven linkage means, discussed in detail below, are provided to cause oscillating rotation of the pivoted frame 18 about the axis 21 in timed relationship to the operation of the machine.

Mounted for longitudinal reciprocation on the forward end of the pivot frame 18 is a transfer slide 22. In FIGS. 2 and 3 this slide 22 is illustrated without transfer gripper fingers mounted thereon. However in use, five similar gripper finger assemblies 23 of the type illustrated in FIGS. 6 and 7 are normally pivoted in bosses 24 on the slide 22 at spaced locations along the slide. The spacing between the gripper transfer assemblies 23 is equal to the spacing between the adjacent die stations in the forging machine. A powered drive as illustrated in FIGS. 9a and 9b is provided to power the slide in its reciprocating movement with respect to the pivoted frame 18. This drive is discussed in detail below.

Supported on the main frame 10 of the machine is a cam shaft 26 which is joumaled for rotation about its axis 27 in shaft supports 28 located at axially spaced locations along the cam shaft 26. Preferably, four shaft supports 28 are provided with two substantially adjaoent to the center portion of the cam shaft and two provided at its ends. The cam shaft 26 is powered in timed relation to the operation of the machine. Normally, it is connected directly to the main machine drive and is arranged to rotate through one complete revolution as the main machine slide moves back and forth through one complete cycle. The cam shaft is provided with a plurality of spaced cams which drive the linkage used to oscillate the support frame 18 and also drive the linkages which operate to control the gripping and release of the transfer fingers carried by the slide 22. Here again, the structural detail and mode of operation of these linkages is discussed in detail below.

The structure of the gripper finger assemblies 23 is illustrated in FIGS. 6 and 7. It should be understood that each of the assemblies 23 is similar, however, their operation can be arranged to provide either turning or non-turning type transfer. Each of the assemblies 23 includes a tubular spindle 31 journaled in bearings 32 in the bosses 24 for rotation about its central axis 33. The axis 33 is vertical and parallel to the die face 34 (illustrated in FIG. 3) when the transfer is in the gripping and releasing positions. The axis 33, however, is pivoted out away from the die face 34 when the pivoted frame 18 is pivoted from the position illustrated in FIG. 3.

Referring to FIGS. 6 and 7, the vertical positioning of the spindle 31 is provided by a spacer 36 positioned against a check spacer assembly 37 on the upper boss 24. The spacer 36 is held against a shoulder 40 by an assembly including a thrust bearing 38, a gear sector 39, and a cylinder 41 of an air spring. Therefore, the spindle 31 is vertically positioned with respect to the slide 22 even though it is free to rotate about a central axis 33.

Mounted on the lower end of the spindle 31 are two gripper finger assemblies 42 and 43 which are pivotally supported on the spindle for limited rotation about the pivot axes 44 and 46, respectively. The two axes 44 and 46 are parallel to each other and are equally spaced from, and are on opposite sides of the central axis 33. The finger assembly 42 includes a finger element 47 which is secured in position by a bolt 48. Similarly, the finger assembly 43 is provided with a finger element 49 mounted by a bolt 51. However, in this instance, an adjustment screw 52 is provided for adjustment of the finger member 49 with respect to its support arm 53.

The gear sector 39 is clamped to the spindle 31 by a bolt 56 when it is desired to rotate the spindle during transfer movement. Each gear sector 39 meshes with a gear rack 57 mounted on the pivoted frame 18 and the sector is proportioned so that as the slide 22 moves with respect to the rack 57 on the pivot frame 18 between the gripping position and the release position, the sector 39 and, in turn, the spindle 31 rotates through 180. When it is desired to arrange the transfer of a particular gripping assembly 23 so that turning does not occur during the transfer movement, the bolt 56 is loosened and the slide is moved until the sectors are clear of the rack. The bolt is then tightened with the sector out of engagement with the rack and an L- shaped lock member 58 is dropped down from its release position illustrated in FIG. 7 until its inner surface 59 engages a flat 61 formed on the spindle. A pair of nuts 62 retain the lock member 58 in either its release position illustrated or its locked position. When the lock member 58 is in the release position a guide pin 63 is located in a bore 64 to insure that the lock member cannot drop down against the flat 61. When it is desired to move the lock member to the locked position, the nuts 62 are merely loosened and the lock member is slipped outward off of the pin and dropped down into the locked position. The tightening of the nuts then causes engagement with the flat 61 which prevents rotation of the spindle with respect to the bosses 24. The lock member 58 is provided with a slottype opening 66 to receive the pin 63 when the member is in the locking position.

Extending down through the spindle 31 is an operating assembly which controls the gripping and release of the fingers 42 and 43. This assembly includes an operating member 67 which is axially movable within the spindle 31 and is resiliently urged in an upward direction with respect to the spindle by a pull rod 68 connected to the piston 69 within the air spring cylinder 41. Air under pressure is admitted to the spring chamber 71 through the fitting 72 and a flexible hose 73 so that the chamber 71 below the piston is pressurized and produces a force urging the piston in an upward direction. This, in turn, through the pull rod 68 which is connected at its lower end to the operating member 67, resiliently urges the operating member in an upward direction. Each flexible hose 73 is connected to a passage 75 in the slide. This passage is, in turn, connected to a supply of pressure by a flexible hose 8 l.

A cross pin 74 at the lower end of the operating member 67 is provided with a bearing 76 which engages the lower side of a lateral arm 77 on the finger assembly 43. Therefore, the force of the air spring tends to cause clockwise movement of the projection 77 as viewed in FIG. 6 and inward or clamping movement of the finger member 49. Positioned above the projection 77 is a second lateral projection provided on the finger assembly 42. In this instance the upward force of the air spring tends to produce anticlockwise rotation of the finger assembly 42 and consequently, inward movement of the finger member 47 toward the finger member 49. A spring plunger 79 within the operator member 67 is urged in a downward direction by a spring 80 and maintains contact between the two projections 77 and 78 and contact between the projecu'ons 77 and the bearings 76. This spring, because it takes up all clearance, insures that the arms both open and close in exact unison even after the machine has operated a sufficient time to develop some wear in the parts. Therefore a blank is uniformly gripped or released in the same manner and in the same location each time the machine cycles and there is no tendency for one finger to operate ahead or behind the other finger. The spring does not support gripping loads but only supplies enough force to cause finger opening. Therefore, a relatively light spring is sufficient.

A cam driven linkage, best illustrated in FIG. 5, is provided to overcome the action of the air spring and functions to control the closing of the gripper fingers for gripping and the opening of the fingers for release in timed relationship to the operation of the machine. Mounted on the cam shaft 26 and associated with each of the gripping assemblies is a gripper control cam 82. In FIG. 1 there are six such cams illustrated even though the slide provides only five gripper assemblies. The left five earns 82 are respectively associated with the five gripper assemblies and independently control the operation of each associated assembly. The right hand cam 82 does not function when the slide 22 is mounted on the transfer. It functions, however, when a substitute slide having a difi'erent type of transfer gripper is mounted on the transfer as will be discussed below.

Associated with each gripping assembly is a tappet link 83 joumaled on a shaft 84 carried by the pivot frame 18. The tappet link is provided with an upstanding projection 86 and a follower arm 87 pivoted at 88 on the projection 86. An adjusting screw 89 is threaded through the upper end of the projection 86 and extends into abutting relationship with a boss 91 on the follower arm 87. With this structure, the position of the follower arm with respect to the tappet arm can be easily adjusted.

Joumaled on the follower arm 87 is a follower roller 92. A spring 93 extending between the pivot frame 18 and the tappet arm 83 biases the tappet arm in a clockwise direction to maintain the follower roller 92 in engagement with a cam. in the drawings, the earns 82 are illustrated as simple cylinders for purposes of illustration. However, it should be understood that they are provided with appropriately positioned lobes which cause oscillating rotation of the tappet arm with respect to the pivot frame 18. The action of the cam 82 causes the follower 92 to move along an arc path around the axis of the shaft 84 as illustrated in FIG. 3 by the dotted line 94. The various elements are proportioned so that this path extends substantially through and is bisected by the axis 21 of pivotal movement of the pivot frame 18. Therefore, the pivoting movement of the frame 18 does not produce any substantial movement of the follower along the periphery of the cam 82 and consequently, the function of the cam and the follower is substantially uneffected by the pivotal movement of the pivot frame 18.

Each tappet lever 83 is provided with a forwardly extending projection 95 with a laterally extending bar 96 mounted on its end. The lower surface of the bar provides a track surface along which a roller follower 97 moves. The roller follower 97 is mounted on a link 98 supported for oscillating rotation by a lateral shaft 99 mounted in the slide 22. Secured to the opposite end of the shaft 99 is a second link 101 having a forked end 102 engageable along diametrically opposite sides with the upper surface of a bearing race 103.

The upper race 103 is part of an antifriction bearing 104 best illustrated in FIG. 7. This bearing is guided and supported by a bushing 106 which is, in turn, connected to the operating member 67 by a cross pin 107. The cross pin 107 extends through a closed slotted opening 108 in the spindle 31 so that the pin is free for limited vertical movement with respect to the spindle. With this structure downward movement of the forked ends 102 as viewed in FIG. 7 causes similar downward movement of the operating member 67 against the action of the air spring. The upward movement of the forked ends 102 is limited by an adjusting screw 109 which functions to adjustably limit the upward movement of the operating member 67 and, in turn, the degree of closing of the finger members 47 and 49.

The gripping and releasing operation is controlled by the rotating cam 82 associated with each finger assembly. As a lobe or high point on the cam moves under the cam follower 92 it causes anticlockwise rotation of the tappet lever 83. This, in turn, causes the followers 97 to be pressed down and results in finger opening movement for releasing a work piece or blank. Of course, as the lobe of the cam moves past the follower 92, the action of the compressed air within the chamber 71 causes finger closing movement as the tappet lever 83 is allowed by the cam 82 to rotate in a clockwise direction. The lower surface of the lateral bar 96 is aligned with the direction of movement of the slide 22. Consequently, the longitudinal movement of the slide does not affect the finger opening and closing operation determined by the cam 82.

As viewed in FIG. 3, it is preferable to arrange alternate tappet levers so that their projections 95 are longer or shorter than the adjacent projections. With this arrangement, one lever does not interfere its adjacent lever even though the lateral bar 96 has a length exceeding the spacing between adjacent gripper assemblies and the length of travel of the slide 22. With this arrangement, of course, the follower lever 98 of each gripping assembly has to be offset from the adjacent follower lever in a similar manner to provide proper alignment with the associated lateral bar 96.

Reference should now be made to FIGS. 1, 3, and 4 which illustrate the linkage for controlling the pivoting movement of the pivoted frame 18 of the transfer. A centrally located cam 111 is mounted on the cam shaft 26 to control the pivoting movement of the frame. The cam 111 is engaged by a roller follower 112 carried by a follower lever 113. The follower lever 1 13 is pivotally connected at 114 to a shaft 116 journaled on the support assembly 16 in bearings 117 illustrated in FIG. 1. A pair of bolt fasteners 118 cooperate with the pivot 114 to lock the follower arm 113 with respect to the shaft 116. Therefore, when the cam 111 causes a lobe to pass under the follower 112, the shaft 116 is caused to rotate in a clockwise direction. Here again, the cam 111 is illustrated as a simple cylinder but it should be understood that the cam would be provided with lobes shaped to produce the required rotation of the shaft 116 in proper timing with the operation of the machine.

Mounted on the opposite ends of the shaft 116 are similar depending arms 119 which are connected at their lower ends with push rods 121. Mounted on the forward end of each push rod is a cam element 122 which engages with a roller follower 123. The roller follower 123 is journaled on the pivot frame 18 at a location spaced from the pivot axis 21 of the frame 18.

When the cam 111 causes clockwise rotation of the shaft 116 the two push rods 121 move forward and through their contact with the follower roller 123 causing clockwise rotation of the pivot frame 18 about its pivot axis 21. Since the pivoting force is applied at opposite ends of the pivot frame 18 there is substantially no tendency for the frame to be twisted by this action.

In order to produce a force in an anticlockwise direction on the pivot frame 18, a pair of similar pneumatic springs 124 are provided. Each of these springs includes a cylinder 126 supported at one end on the main frame 14 and a piston connected at 127 to an upstanding arm 128 integrally formed on the pivot frame 18 at each end thereof. These springs resiliently urge the pivot frame toward the operative position illustrated in FIG. 3, but allow the pivot frame to be rotated in a clockwise direction from this position by the cam 111. However, since the springs 124 are connected between the main frame 12 and the pivot frame 18, they do not hinder the raising of the two frames to the service position after the hold down clamps 17 are released.

The longitudinal reciprocation of the slide 22 is provided by a drive mechanism as illustrated in FlGS. 9a and 9b. This mechanism includes a cam 131 powered by the main machine drive which engages a follower 132 on a follower arm 133. The follower arm is pivoted at its lower end so that the passage of a lobe on the cam 131 under the follower 132 causes movement of the upper end of the follower arm 133 to the right as viewed in FIG. 9a.

Connected to the upper end of the follower arm 133 is a push rod 134 which is, in turn, connected to a gear rack extension 136 on the piston 137 of an air spring 138. The rack extension 136 is guided within a gear box 139 mounted on the forward end of the spring 138. The rearward end of the spring is pivotally supported on the machine frame at 141.

Journaled on the gear box 139 is a drive element 142 of an overload clutch. The drive element is connected to a gear 143 which meshes with the rack extension 136 and is caused to rotate when the rack extension reciprocates. The driven member 144 of the overload clutch 142 is connected to a shaft 146 having a crank member 147 mounted at its upper end.

The clutch assembly is maintained in its engaged position by a spring assembly including a spring 148 which resiliently biases a pivoted crank 149 in a clockwise direction and thereby causes a pin 151 to engage the underside of the gear box 139 to press the drive element 142 into operative engagement with the driven element 144. However, when the torque which must be transmitted between the two elements 142 and 144 exceeds a predetermined value determined by the force of the spring 148, the drive element 142 is cammed down against the action of the spring 148 causing the entire spring assembly 138 to pivot around the axis 141 to a clutch disengaged condition. It should be noted however, that during such downward movement created by an overload condition on the clutch, there is no lateral relative movement between the gear 143 and the rack extension 136 so the force of engagement therebetween by the load does not resist the declutching operation and does not affect the torque value at which the clutch will release. With this structure, the torque that can be transmitted by the clutch is determined only by the setting of the spring 148 and the clutch functions to release in a reliable manner when the desired maximum torque is applied to the clutch. The clutch is normally set so that a positive drive is maintained and its principal purpose is to prevent damage to the transfer mechanism in the event that a jam occurs.

The air spring 138 is provided with an integral reservoir 151 by a cylinder member 152 which extends around the cylinder sleeve 153 within which the piston 137 reciprocates. The cross sectional area of the cylinder 153 is substantially smaller than the cross sectional area of the reservoir 152, so the volume of the reservoir is substantially greater than the volume displaced by the piston 137. Consequently, the spring provides substantial stroke of the piston without excessive variations in the pressure of the air within the device. The reservoir is connected through a pressure supply line 154 to a controlled source of pressure. However, since substantial volume is provided within the reservoir 151, very little flow is required through the supply line and excessive heating in the supply line does not occur.

The slide 22 is connected to the crank arm 147 by a drive link 156 which extends between the crank and a ball joint fitting 157 on the end of the slide 22. In operation, the cam 131 causes reciprocating movement of the follower arm 133 which is converted by the rack and gear drive to oscillating rotation of the crank 147. This, in turn, produces the required reciprocating movement of the slide 22. In the event of a jam that places excessive load on the drive, the drive element 142 of the clutch moves downward against the action of the spring 148 to prevent excessive forces from being applied to the transfer itself.

In some instances it is desirable to remove the slide 22 from the transfer and to substitute a different slide having either a different type of gripper fingers or gripper fingers which are adjusted to transfer a different type of work piece. In such instance, it is merely necessary to disconnect the drive link 156 from the crank arm 147 and disconnect the hose 81. When this is done, the slide 22 is pulled out of its transfer along its guide without disconnecting any of the hoses 73 which individually connect the finger air springs to the longitudinal air passage extending lengthwise along the slide 22. Therefore, it is not necessary to disconnect each finger biasing air spring individually to permit removal of the slide 22. In other instances, when the finger assemblies are being adjusted, it is desirable to permit release of the pneumatic spring force so that the fingers can be manually opened or closed. Since all of the air springs on a given slide are pressurized through the single hose 81, a quick disconnect is used to release the air pressure to all of the finger operating springs. However, after the adjustment is completed, the springs can be again pressurized by merely reconnecting the hose 81.

In some instances, a different type of transfer frnge assembly is required for the manufacture of a particular type of work piece. For example, when the machine is used for the manufacture of headed articles or relatively long articles which do not require any turning during transfer, a transfer gripper of the type illustrated in FIG. 8 may be used. Such transfer fingers again provide opposed gripper finger elements 161 and 162 which are pivotally supported on a slide (not illustrated) and are biased toward their closed or gripping position by a pneumatic spring 163.

Finger opening and closing is controlled by the same cam driven linkage illustrated in FIG. 5. Since the linkage is the same, similar reference numerals apply to the various elements. In the transfer illustrated in FIG. 8, however, the follower arm 164 extends to the right and is provided with a cam follower 166 which engages the lateral bar 96. When the cam 82 causes downward movement of the bar 96 a follower arm 164 is caused to rotate in a clockwise direction. This produces an opening movement of the two fingers 161 and 162 against the action of the spring 163. Conversely, when upward movement of the bar 96 occurs in response to the movement of the cam 82, the spring 163 causes the fingers to close for gripping a blank. Because the follower arrri 164 extends to the right in the transfer illustrated in FIG. 8 which is the opposite direction of the extension of the follower arm 98 of the transfer illustrated in FIG. 5, the five cams 82 on the cam shaft 26 to the right as viewed in FIG. I operate the gripper fingers and the cam 82 at the left end of the cam shaft does not function.

Transfers of the type illustrated in FIG. 8 are preferred when transferring articles which are headed at their ends such as bolt blanks or the like, since the fingers can be opened wider than the fingers of the type illustrated in FIGS. 6 and 7. The transfer illustrated in FIG. 8 does not permit turning of the blank during the transfer operation. In most instances, when turning is not required, the pivoting of the frame 18 is also not required. When this condition exists, the bolts 118 are removed to allow the follower arm 1 13 to be pivoted up away from the cam 11]. By this simple expediency, the mechanism for pivoting the pivot frame 18 can be rendered inoperative. On the other hand, when pivoting of the pivot frame 18 is required, reconnecting of the follower arm 113 by means of the bolts 118 is easily accomplished.

The slide supporting the type of fingers illustrated in FIG. 8 can be installed easily or removed in the same manner as the slide 22. In practice, the slide is merely moved along the guideways to the installed position and is connected at its end by the drive link 156. Here again, the slide is preferably provided with axial passage along which air under pressure is supplied to a position adjacent to each of the springs 163. These springs are connected to individual hoses 166 to the passage in the supporting slide.

When the transferring is equipped with gripper finger assemblies of the type illustrated in FIGS. 6 and '7, the various cams are arranged so that the slide 22 is at one extreme position of its movement and the fingers are located adjacent to the pickup or gripping position. At this time, the pivoted frame is in the position illustrated in FIG. 3 and the gripper fingers are positioned immediately adjacent to the die station at which gripping is required. When the blank or work piece is ejected from the die into the fingers, the earns 82 allow the fingers to close and grip the blank. The cam 11] then operates to pivot the pivot frame 18 up around its pivot axis 21 as the slide 22 commences to move lengthwise of the transfer toward the delivery position. By pivoting the frame 18 up from the position of FIG. 3, the fingers are moved away from the face of the die breast 34 to provide clearance so that the fingers can be rotated. When the slide reaches its other extreme of movement, the fingers are positioned adjacent to the delivery position or die station and the cam 111 allows the pivot frame 18 to return to its initial condition. At this time the fingers are adjacent to the subsequent die station or delivery position and the blank is then moved by the associated tool into the subsequent die. As this occurs, the cams 82 function to open the fingers to release the work piece and to clear the tool. Since all of the three drives of the transfer are powered by the main machine drive, the operation of the three drives is synchronized with the operation of the machine and with the operation of the other drives.

Because a machine incorporating this invention can be easily modified to provide a transfer system operable to transfer different types of parts, the machine can be used to manufacture a large variety of work pieces. Therefore, it is not necessary to have several different types of machines to obtain the ability to manufacture a large variety of parts.

Although preferred embodiments of this invention are illustrated it is to be understood that various modifications and rearrangements of parts may be resorted to without departing from the scope of the invention disclosed and claimed herein.

WHAT IS CLAIMED IS:

1. A machine for forging work pieces comprising a main frame assembly for supporting a plurality of dies at laterally spaced die stations, a transfer assembly operable to progressively transfer work pieces laterally between said die stations, said transfer assembly including a rotatable cam shaft joumaled on said main frame assembly and extending laterally with respect thereto, a first transfer housing pivoted on said main frame assembly for oscillating rotation about a first axis parallel with said cam shaft, a first slide reciprocably mounted on said first transfer housing for movement laterally of said main frame assembly and oscillating movement about said first axis with said first transfer housing, first work piece gripping means on said slide providing fingers operable to grip a work piece at one die station and operable to turn such work piece end-for-end while transferring it to a subsequent die station, a first linkage powered by said cam shaft operable to oscillate said first transfer housing about said first axis in timed relationship to the operation of said machine, a second linkage powered by said cam shaft operable to control gripping and release of said fingers independent of turning thereof and in timed relationship to the operation of said machine, and drive means operable to reciprocate said slide in timed relationship to the operation of said machine.

2. A machine for forging work pieces as set forth in claim 1 wherein turning means are provided to turn said fingers in response to relative movement between said slide and transfer housing.

3. A forging machine as set forth in claim 2 wherein said turning means are releasable to permit said fingers to transfer a work piece without turning, and lock means are provided to prevent turning of said fingers.

4. A forging machine as set forth in claim 1 wherein said first linkage includes a connection which is releasable to render said first linkage inoperable, and a second slide is provided for mounting on said transfer housing to replace said first slide, said second slide being provided with second work piece gripping fingers for transferring work pieces between said die stations without turning, said second linkage being operable to control the gripping and releasing of said second fingers.

5. A machine for forging work pieces as set forth in claim 1 wherein said second linkage includes a cam on said cam shaft, a link pivoted on said first transfer housing, and follower means on said link engageable with said cam and movable along a path substantially through said first axis in response to rotation of said earn.

6. A machine for forging work pieces as set forth in claim 5 wherein said path is substantially bisected by said first axis, and spring means are connected between said link and first transfer housing resiliently urging said follower means toward said cam.

7. A machine for forging work pieces as set forth in claim 1 wherein said cam shaft rotates about a second axis spaced from and parallel to said first axis.

8. A transfer assembly for forging machines or the like comprising a support, a tubular spindle joumaled on said support for rotation about its central axis, a pair of opposed gripper fingers pivoted on said spindle for opening and closing movement in a direction normal to said central axis, said fingers being symmetrical with respect to said axis and being adapted to grip a work piece located on said axis, each finger providing an operating projection extending to said central axis, an operating assembly extending along said spindle and axially movable relative thereto, axial movement of said operating assembly moving said operating projections and causing opening and closing movement of said fingers, a fluid pressure spring mounted along said axis resiliently biasing said operating assembly in one direction, an external operating surface on said operating assembly extending substantially normal to said axis, a link pivoted on said support having a portion engaging said operating surface operable to move said operating assembly against the action of said fluid spring and control the opening and closing of said fingers.

9. A transfer assembly as set forth in claim 8 wherein said operating surface is intermediate the ends of said spindle, and said spindle is provided with lateral openings, said operating assembly including connecting means extending through said openings connecting said external operating surface and the internal portion of said operating assembly.

10. A transfer assembly as set forth in claim 8 wherein said fluid spring includes a cylinder mounted on the end of said spindle opposite said fingers, and an axially movable piston connected to said operating assembly.

11. A transfer assembly as set forth in claim 10 wherein said transfer includes a frame, said support is a slide reciprocable relative to said frame, turning means interconnecting said spindle and frame operate to turn said spindle in response to reciprocation of said spindle with said slide.

12. A transfer assembly as set forth in claim 11 wherein said turning means is releasable to render it inoperative, and stop means are provided to prevent rotation of said spindle relative to said slide.

13. A transfer assembly as set forth in claim 8 wherein a plurality of similar gripper assemblies are mounted on said support, said support is provided with fluid pressure conduit means connected to supply fluid under pressure to said fluid spring of each gripper assembly.

14. A transfer assembly as set forth in claim 13 wherein said transfer includes a frame, said support is a slide reciprocable relative to said frame, and said conduit means include a flexible portion connecting said slide to a source of fluid under pressure to accommodate the reciprocation of said slide.

15. A transfer assembly as set forth in claim 14 wherein said flexible portion is provided with a coupling, disconnecting said coupling operating to release the pressure in each of said springs, each fluid spring being connected to its associated spindle and turning therewith with respect to said slide, and a flexible line connects each fluid spring and said conduit means to accommodate such turning movement.

16. A transfer assembly as set forth in claim 8 wherein said operating assembly includes bearing means engageable with one of said operating projections, the other of said operating projections engaging said one operating projection on the side thereof opposite said bearing means, and a spring urging said other operating projection toward said bearing means.

17. A machine for forging work pieces comprising a ain fr e asse l for su rti a die at a die staii on, a s ll 3e on saTitiame fo n oviii g a tool toward and away from said die station, a transfer operable to transfer work pieces from a first position to said die station including work piece gripping means movable from a first position in which it grips a work piece to a second position in which it delivers said work piece to said die station, a mechanical drive for said transfer, said mechanical drive including an overload clutch providing a drive clutch member and a clutch driven member, said clutch members being connected to transmit torque therebetween when in a drive position and being movable relative to each other to a release position when the torque applied therebetween exceeds a predetermined value, drive means including mating gears connected to drive said drive clutch member, and support means mounting said mating gears permitting their movement in unison with said drive member when it moves to said release position.

18. A machine as set forth in claim 17 wherein said drive means includes a fluid spring including piston and cylinder elements operable to resiliently urge said gears in one direction, one of said elements being pivotally supported on said frame at a location spaced from said gears, said support means being on said one element, movement of said clutch members to said release position causing pivotal movement of said one element.

19. A machine as set forth in claim 18 wherein said one element is the cylinder element of said fluid spring, said cylinder element providing an integral reservoir having a volume substantially greater than the volume displaced during operation of said spring, and a supply line connecting said reservoir to a source of fluid under pressure. 

1. A machine for forging work pieces comprising a main frame assembly for supporting a plurality of dies at laterally spaced die stations, a transfer assembly operable to progressively transfer work pieces laterally between said die stations, said transfer assembly including a rotatable cam shaft journaled on said main frame assembly and extending laterally with respect thereto, a first transfer housing pivoted on said main frame assembly for oscillating rotation about a first axis parallel with said cam shaft, a first slide reciprocably mounted on said first transfer housing for movement laterally of said main frame assembly and oscillating movement about said first axis with said first transfer housing, first work piece gripping means on said slide providing fingers operable to grip a work piece at one die station and operable to turn such work piece end-for-end while transferring it to a subsequent die station, a first linkage powered by said cam shaft operable to oscillate said first transfer housing about said first axis in timed relationship to the operation of said machine, a second linkage powered by said cam shaft operable to control gripping and release of said fingers independent of turning thereof and in timed relationship to the operation of said machine, and drive means operable to reciprocate said slide in timed relationship to the operation of said machine.
 2. A machine for forging work pieces as set forth in claim 1 wherein turning means are provided to turn said fingers in response to relative movement between said slide and transfer housing.
 3. A forging machine as set forth in claim 2 wherein said turning means are releasable to permit said fingers to transfer a work piece without turning, and lock means are provided to prevent turning of said fingers.
 4. A forging machine as set forth in claim 1 wherein said first linkage includes a connection which is releasable to render said first linkage inoperable, and a second slide is provided for mounting on said transfer housing to replace said first slide, said second slide being provided with second work piece gripping fingers for transferring work pieces between said die stations without turning, said second linkage being operable to control the gripping and releasing of said second fingers.
 5. A machine for forging work pieces as set forth in claim 1 wherein said second linkage includes a cam on said cam shaft, a link pivoted on said first transfer housing, and follower means on said link engageable with said cam and movable along a path substantially through said first axis in response to rotation of said cam.
 6. A machine for forging work pieces as set forth in claim 5 wherein said path is substantially bisected by said first axis, and spring means are connected between said link and first transfer housing resiliently urging said follower means toward said cam.
 7. A machine for forging work pieces as set forth in claim 1 wherein said cam shaft rotates about a second axis spaced from and parallel to said first axis.
 8. A transfer assembly for forging machines or the like comprising a support, a tubular spindle journaled on said support for rotation about its central axis, a pair of opposed gripper fingers pivoted on said spindle for opening and closing movement in a direction normal to said central axis, said fingers being symmetrical with respect to said axis and being adapted to grip a work piece located on said axis, each finger providing an operating projection extending to said central axis, an operating assembly extending along said spindle and axially movable relative thereto, axial movement of said operating assembly moving said operating projections and causing opening and closing movement of said fingers, a fluid pressure spring mounted along said axis resiliently biasing said operating assembly in one direction, an external operating surface on said operating assembly extending substantially normal to said axis, a link pivoted on said support having a portion engaging said operating surface operable to move said operating assembly against the action of said fluid spring and control the opening and closing of said fingers.
 9. A transfer assembly as set forth in claim 8 wherein said operating surface is intermediate the ends of said spindle, and said spindle is provided with lateral openings, said operating assembly including connecting means extending through said openings connecting said external operating surface and the internal portion of said operating assembly.
 10. A transfer assembly as set forth in claim 8 wherein said fluid spring includes a cylinder mounted on the end of said spindle opposite said fingers, and an axially movable piston connected to said Operating assembly.
 11. A transfer assembly as set forth in claim 10 wherein said transfer includes a frame, said support is a slide reciprocable relative to said frame, turning means interconnecting said spindle and frame operate to turn said spindle in response to reciprocation of said spindle with said slide.
 12. A transfer assembly as set forth in claim 11 wherein said turning means is releasable to render it inoperative, and stop means are provided to prevent rotation of said spindle relative to said slide.
 13. A transfer assembly as set forth in claim 8 wherein a plurality of similar gripper assemblies are mounted on said support, said support is provided with fluid pressure conduit means connected to supply fluid under pressure to said fluid spring of each gripper assembly.
 14. A transfer assembly as set forth in claim 13 wherein said transfer includes a frame, said support is a slide reciprocable relative to said frame, and said conduit means include a flexible portion connecting said slide to a source of fluid under pressure to accommodate the reciprocation of said slide.
 15. A transfer assembly as set forth in claim 14 wherein said flexible portion is provided with a coupling, disconnecting said coupling operating to release the pressure in each of said springs, each fluid spring being connected to its associated spindle and turning therewith with respect to said slide, and a flexible line connects each fluid spring and said conduit means to accommodate such turning movement.
 16. A transfer assembly as set forth in claim 8 wherein said operating assembly includes bearing means engageable with one of said operating projections, the other of said operating projections engaging said one operating projection on the side thereof opposite said bearing means, and a spring urging said other operating projection toward said bearing means.
 17. A machine for forging work pieces comprising a main frame assembly for supporting a die at a die station, a slide on said frame for moving a tool toward and away from said die station, a transfer operable to transfer work pieces from a first position to said die station including work piece gripping means movable from a first position in which it grips a work piece to a second position in which it delivers said work piece to said die station, a mechanical drive for said transfer, said mechanical drive including an overload clutch providing a drive clutch member and a clutch driven member, said clutch members being connected to transmit torque therebetween when in a drive position and being movable relative to each other to a release position when the torque applied therebetween exceeds a predetermined value, drive means including mating gears connected to drive said drive clutch member, and support means mounting said mating gears permitting their movement in unison with said drive member when it moves to said release position.
 18. A machine as set forth in claim 17 wherein said drive means includes a fluid spring including piston and cylinder elements operable to resiliently urge said gears in one direction, one of said elements being pivotally supported on said frame at a location spaced from said gears, said support means being on said one element, movement of said clutch members to said release position causing pivotal movement of said one element.
 19. A machine as set forth in claim 18 wherein said one element is the cylinder element of said fluid spring, said cylinder element providing an integral reservoir having a volume substantially greater than the volume displaced during operation of said spring, and a supply line connecting said reservoir to a source of fluid under pressure. 